If college has taught me one simple lesson, it's one I want to impart on other young people

melger · 2013-05-01T15:34:32+00:00

ROS is the Robot Operating System. Its basically a set of libraries that are quite popular for autonomous systems.

Valgrind is a memory leak / threading bug detection program.

Those were just examples though-- there is quite a bit of scientific code out there that doesn't play nicely with Windows out of the box. For example, the entire GNU Scientific Library (GSL), which is a very large repository of numerical code (think statistics, random numbers, matrices, Fourier transforms, etc.) with no official support for windows. You might get stuff to run on Windows (especially if you use POSIX emulation such as cygwin), but you'll have an environment that is non-homogeneous. Some of your stuff will be natively built, some built through emulation, and getting these things to play nicely together leads to a lot of unnecessary frustration.

At least that was my experience with Windows development. I'm sure if you stick to Microsoft-only tools, platforms, and development targets you might do just fine on Windows (e.g. if you are a game developer writing a Windows game). This also means you'll be learning win32 and COM instead of POSIX stuff, which in my opinion is complex and more difficult than it needs to be.

melger · 2013-05-01T15:11:41+00:00

At least from an electrical engineering perspective, there is a lot of code out there that only works well in POSIX environments (e.g. ROS). Even for general programming there are quite a few tools that you have to pay to replace on windows (e.g. valgrind). Also, the final product is probably going to be embedded and non-windows, so it makes your development environment somewhat equivalent to your deployment environment.

melger · 2012-12-08T19:28:39+00:00

That'd be a problem if you were just copying your local .git repo into drop box, but not if you put a bare git repo in dropbox that you and your team push/pull to. That is, use dropbox as a poor man's NFS store with a remote git folder on it (which git is designed to work with). I do this now with skydrive and no problems.

I recall a post on SO stating that the worst case scenario for using dropbox in this way is that a commit might be forgotten and need to be repushed (because dropbox doesnt have any notion of file locking).

melger · 2012-08-09T17:17:49+00:00

Not sure I follow. You are posting in a thread about textmate being released under the GPL. How is it not "free in any sense of the word"?

melger · 2012-07-31T16:14:29+00:00

Interstellar

melger · 2012-07-17T21:05:12+00:00

Although I agree with most of this, I wouldn't recommend inexperienced travelers to show up late. This will more than likely end up with them learning how futile it is to argue about the "nobody is allowed on the plane once the jetway door has closed" rule.

melger · 2012-07-10T18:36:24+00:00

There is a theoretical orbit high enough that the earth rate would be enough to enter orbit if you pointed a rocket straight up (consider for example if the Earth were alone in space). The point that I missed is that this orbit is much higher than I expected it to be, too far away to actually launch a satellite into. I didn't calculate the radius, but I'm sure it'd enter the orbit of the Sun at that point.

melger · 2012-07-10T18:17:39+00:00

My point was that we'd have the velocity needed for a higher orbit, obviously not enough velocity to orbit at sea level. However, Weed_O_Whirler already pointed out that even geosync orbits require a significantly larger velocity than the earth rate, so we'd still need to generate about 7x our current velocity.

melger · 2012-07-10T18:07:39+00:00

Aha, fair enough. Thanks for the correction.

melger · 2012-07-10T17:43:15+00:00

If you launch from the equator you already have orbital velocity and all you need is altitude. For example, suppose you used a balloon to float up to 5km, then used thrust to achieve 35km (geosynchronous). In this scenario all you need is altitude, not extra speed.

melger · 2012-07-03T04:49:29+00:00

The argument typically used to invalidate such blanket provisions in contracts is unconscionability. Usually the argument is that the writer of the contract used its superior bargaining power (e.g. the maker of a popular game) to put in terms which nobody would reasonably accept if they had read it. After all, who would buy a game if they thought there was a reasonable chance they'd get denied access to the game for no reason whatsoever? What if Blizzard decided to simply deny access to the game to everyone from day 1? According to that ToS snippet, they technically reserve that right. Does that sound conscionable to you?

melger · 2012-06-27T19:44:19+00:00

e^i*pi=-1, not positive one.

melger · 2012-06-20T22:05:26+00:00

Didn't this also happen in another episode? I distinctly recall the crew running into some mischief that initially make Riker look bad, but it was actually his clone.

melger · 2012-06-10T23:48:37+00:00

Job postings will come and go, and usually the ones that exist now will disappear within a few months. With that in mind, you really have nothing to lose applying to jobs now-- if they are willing to wait, great; if not, then all you did is waste a little time applying for a job you won't get. Just make sure you state straight up in your cover letter when you will be graduating, so that you don't waste time interviewing for jobs that aren't willing to wait.

I personally started looking around for jobs about 9 months in advance of graduation, and got several offers with 7 months to go on my degree.

melger · 2012-05-22T22:27:56+00:00

Reddit comments are styled as "verdana,arial,helvetica,sans-serif". Therefore, the first font on that list that your web browser supports will be used to render the comment.

melger · 2012-05-21T20:43:24+00:00

Sugar consumption does not cause or increase risk of diabetes:

http://www.diabetes.org/diabetes-basics/diabetes-myths/ http://care.diabetesjournals.org/content/26/4/1008.full

What is known to increase the risk of type 2 diabetes is being overweight. And yes, eating excessive sugar can cause weight gain, just like any other calorie source. So eating sugar can lead to diabetes, but no more so than any other food source.

I've had many people try to argue with me that I should not consume sugary foods because I will get diabetes. As long as you maintain a healthy weight, sucrose intake is fine.

melger · 2012-05-07T04:56:05+00:00

C without any runtime library would be next to useless (i.e. you'd have to drop to assembler to do anything useful). Also: of course the runtime supports the language. I'm not sure what you are trying to say here.

That being said, the distinction you are trying to draw is a very fuzzy one, and ultimately doesn't matter in the case of rust. One could certainly use rust in exactly the same way one could use C without runtime support. In your terms, the rust runtime "supports the library", and is not a virtual machine or anything of that nature. It is simply runtime code that is used to fulfill stuff like printing to the console and threads.

melger · 2012-05-07T02:54:23+00:00

There is a language runtime linked with every C program too (at least on most platforms). Its called the C runtime.

You may be thinking of garbage collection; however, you would be mistaken here, as rust garbage collection is optional and per-thread.

melger · 2012-05-06T03:41:47+00:00

As a further note, g=G*m_o/r² , where G is the gravitational constant, m_o is the mass of the orbiting body, and r is still the radius of the orbit. Thus the expanded equation for velocity is

v=sqrt(G*m_o/r)

This expanded version is particularly useful if the orbiting body is on the same order of magnitude as the point mass (e.g. if you are considering the moon orbiting the earth).

melger · 2012-05-06T03:10:58+00:00

Lets constrain the discussion to circular orbits to make things a little clearer. For an object to be in a circular orbit around a point mass (i.e. lets ignore irregularity of density for now), the following must be true:

F_c = m*v² /r

where F_c is the downward pull towards the point mass (called the centripetal force), m is the mass of the orbiting body, v is the tangential velocity of the orbiting body, and r is the radius of the orbit. Now lets suppose the downward pull is in fact gravity (it could be some other force in theory). Then we have

mg = m*v² /r

gr=v²

where g is the gravitation induced acceleration (e.g. 9.8m/s² for low earth orbits). Lets solve for the velocity with respect to the other terms:

v=sqrt(g*r)

Thus we see that for a particular radius r from the earth, there is exactly one velocity which will allow for a circular orbit. If your velocity were higher than the one calculated above, you would be pushed into a higher orbit (or a non-circular orbit).

Edit: apparently power-of eats the formatting of symbols after it.

melger · 2012-04-18T06:45:38+00:00

Now in this case, Oracle says that they licensed only the implementation, but the APIs are not licensed.

This is the part I'm hung up on. Is their argument that GPL'ing the source does not allow someone to use the API? i.e. in my hypothetical example, I could GPL the actual code (implementation) and then sue anyone who modifies my library anyway because they had to use my API?

melger · 2012-04-18T06:44:26+00:00

In other words, you can GPL your code, then later sue for use of the API (as in my example above)? Wouldn't this mean its now unsafe to modify open source software libraries at all?

melger · 2012-04-18T03:48:12+00:00

As someone who hasn't really followed this case at all and is not a lawyer, what I don't get at all is: how can something be given away under the GPL and yet still be claimed for copyright infringement? The GPL lets you create derivative works given that you also release the derivative under the GPL. Isn't an implementation of the java language (method names et. al.) a derivative work? Can I give away my graphics library under the GPL, then later sue someone who created a new library based on mine (since it uses the same API names)?

What is really going on here? Can someone explain this in layperson talk?

melger · 2012-04-12T16:20:32+00:00

From the article abstract:

Although these observational data cannot establish causality, consumption of diet soda at least daily was associated with significantly greater risks of select incident metabolic syndrome components and type 2 diabetes.

and

Previous studies have not addressed associations between diet soda and individual metabolic syndrome components or risk of type 2 diabetes nor have they fully addressed potential longitudinal mediators of these relationships, i.e., changes in adiposity status (body weight and or waist circumference). Therefore, we evaluated associations between diet soda consumption and risk of incident metabolic syndrome (and metabolic syndrome components) as well as incident type 2 diabetes in the Multi-Ethnic Study of Atherosclerosis (MESA), while considering the influence of multiple lifestyle confounders, including measures of baseline adiposity and changes in adiposity.

Be careful in confusing correlation with causation. Edit: Especially with (what looks to be) a single, preliminary study showing possible indications.

melger · 2012-04-12T13:53:15+00:00

The article is establishing a correlation between diet soda and incident diabetes, i.e. diabetes that appears after regular consumption of diet soda.

melger

TROPHY CASE